Variable speed power-transmitting device



Jan. 11, 1938. c. DE LA BARRE DE NANTEUIL 2,105,136

VARIABLE SPEED POWER TRANSMITTING DEVICE Filed May 16', 1956 sSheets-Sheet 1 Fig.1. Feb.

BY AT-JI'ORNEVS CHRISTIAN Jan. 11, 1938. c. DE LA BARRE DE NANTEUIL2,105,136

VARIABLE SPEED POWER TRANSMITTING DEVICE INVENTOR: CHRISTIA DE LA BARREDE NANTEUILJ 5y QZAWZ TORNEV6 Filed May 16, 1936 s Sheets-Sheet 2 Jan.11, 1938. c. DE LA BARRE DE NANTEUIL 2,105,136

VARIABLE SPEED POWER TRANSMITTING DEVICE Filed May 16, 1936 3Sheets-Sheet 3 INVENTOR= CHRISTIAN DE LA BARRE DE NANTEUJL ATTomvm sPatented Jan. 11, 1938 VARIABLE SPEED POWER-TRANSMITTING DEVICEChristian de la Barre de Nanteuil, Versailles, France Application May16, 1936, Serial No. 80,116 In France May 21, 1935 Claims.

Change speed gears are known which are substantially constituted by anepicyclic gear one of the elements of which (sun wheel, or platecarrying the planet pinions) is actuated by a driving shaft, whilstanother of these elements actuates the driven shaft, the third beingsubjected to a braking stress adjustable at will, for allowing theactuation of the driven or receiving shaft at variable speeds. Theinconvenience of such a system precisely resides in this braking action,which considerably reduces the efficiency of such apparatus, thisefficiency becoming acceptable only when the braking action issufiicient for completely stopping the motion of the member on which itis exerted.

For avoiding this inconvenience as much as possible, it has already beenproposed to replace the brake by a worm and worm wheel device, the

inclination of the worm being so chosen that the irreversibility. Theinconvenience of such a system is the mechanical complication resultingfrom the use'of aworm and worm wheel.

The main object of the invention is to avoid this inconvenience, thatisto say to avoid the use of a worm and worm wheel. It is mainlycharacterized by the'fact that the member of the epicyclic gear, themovement of which must be controlled by an external friction, actuateswith an eccentric movement a journal eccentrically fitted within anintermediate member capable of retating; the value of the eccentricityis chosen, according to the friction coefiicients and to the spaceavailable, in order that the system should be as near as possible to thelimit of irreversibility; when the system is irreversible, thereceivoperation can moreover be combined, and in. both cases, thebraking action to be exerted is extremely small.

The accompanying drawings illustrate, by way of example, someembodiments of the invention.

Fig. 1 15a sectional elevation of a first embodiment and Fig. 2 is apartial side View.

Fig. 2a is a partial section on the line II--II of 5 Fig. 1.

Fig. 3 is an explanatory diagrammatic view.

Figs. 4, 5 and 6 are diagrammatic views of modifications.

Fig. 7 is a sectional elevation of a second embodiment.

Fig. 8 is a sectional elevation of a third embodiment.

Figs. 9 and 10 are diagrammatic views of modifications. In the form ofconstruction illustrated in Figs.

1 and 2, onthe driving shaft 5 is rigidly secured, for instance by meansof a key 3, a sun wheel 2. The sun wheel 2 meshes with planet pinions land 5, shown as being two in number, but which might of course be morenumerous, or, on the contrary, reduced to one. The spindles E5 and l ofthe planet pinions 4 and 5 are carried by plates 8 and 9 looselyrotating on shaft I. The spindles Band. I freely rotate in the plates 8and 9 and they extend beyond both sides of these plates.

On one side, they carry pinions NJ and II, which mesh with the drivensun wheel l2. The driven shaft is indicated at It.

On the other side, the spindles 6 and I carry pinions l4 and I5respectively meshing with the teeth l5a and it of a third sun wheel llloosely mounted on an eccentric boss it carried by plate 8. For greaterclearness, it will first be assumed that the ratios of the teeth are soestablished that, if the plates 8 and 5 were assumed to be fixed, thesun wheels i2 and H would rotate at the same speed. although the axis ofrotation of ll is not the same as the axis of rotation of l2. Finally,the journal 20 of sun'wheel H is fitted, through a ball'bearing l9, in'amember 2| supported by a ball bearing 22 concentric with shaft I.

In the diagrammatic view of Fig. 2, the journal 29, member 2! andbearing 22 are illustrated. The latter is herein shown as a smoothbearing external to member ill, but it is shown as being internallyarranged in Fig. 1, and inner crown wheel 22a shown in Fig. 1 rotateswith the driving shaft.

Let f be the direction of rotation of the engine- (Fig. 3). If theplates 8 and 9 are assumed to be fixed, the journal 20 will rotate inthe direc-' tion of the arrow but about the axis B, whereas the crownwheel 22arotates about the axis A.

The ratio p being in this form of construction smaller than 1, and thespeed of the driven shaft, to which the resistant torque is applied,naturally tending towards zero, it will be seen that we is negative,that is to say the plates 8 and 9 tend to rotate in a direction reverseto f. Therefore, the axis B tends to rotate about A in a directionreverse to that indicated by the arrow 1.

The stress tending to produce this gyration is exerted at C on member2|, the radius BC being at right angles to the eccentricity AB. Owing tothe fact that the pinion 29 rotates in the direction of the arrow f, thestress exerted at C is inclined according to the friction angle 0relatively to the radius BC. This stress E encounters at F the bearing22 which exerts a radial reaction, that is to say a reaction directedaccording to FA, but again inclined according to the friction angle 1owing to the rotation of the crown wheel 22a in the direction of thearrow 1. The reaction is therefore directed towards G.

Three cases can occur:

either the resultant of E and of G is positive (direction of f) -or itis null, or it is negative (direction reverse to f) It is first to bementioned that the second case can occur only for a strictly determinedvalue of (p. New, in practice, 0 is variable between certain narrowlimits. This case is therefore purely theoretical and correspondsmoreover to a position of instability which must be approached as muchas possible, as will be explained, without however reaching it.

It is therefore important to determine the conditions of this positionof instability.

A perpendicular AL is dropped to FG and a perpendicular AK is dropped toCE. The condition of null resultant signifies that CE and FG are on thesame straight line, therefore that:

AL==AK (1) Now:

AL=R sin (p R being the radius of the bearing.

AK=AC sin (ot(p) or being the angle AGE (1) becomes therefore:

R sin :14.0 sin (a p) (2) But AC cos oa=T r being the radius of thejournal 20. Therefore sin o C S Sin (0:

r Sln 05 C05 8111 C05 0! COS w s 6 being the eccentricity AB.

The resultant of E and G will be positive when:

1p being the smallest value assumed in practice by and the resultantwill be negative when:

In this case, it is obvious that, in the absence of any other externalforce', the member 2| is driven in the direction of rotation of theengine, and, consequently, the axis B rotates about A in the directionof the engine and at the same speed. Therefore, we wi and consequentlywn=w1. It is the direct drive, and everything exactly occurs as if theshafts l and 13 were rigidly connected to each other.

The eccentricity e is so chosen that it approximates (R+1")tg In theseconditions, the torque driving the member 2! (and consequently, theplates 8 and 9) is only a very small fraction or" the torque transmittedby the engine to the driven shaft. Therefore, a small braking stressexerted on member 2! by means of the brake 25, will be sufficient forslowing down its movement or even for stopping it, that is to say forcausing wo to pass from its maximum value which is on to zero. Thisvariation in the value of we also causes am to vary, wn passing from thevalue on (when we wi) to poll (when we=0). A progressive change ofspeed, between the speeds cal and pwl for the driven shaft is thusensured, and this result has been obtained by a very small externalbraking stress. The efficiency therefore remains very satisfactory, evenduring the intermediate periods between the extreme speeds. For theselatter, there is no loss of energy since: either there is no braking(direct drive), or the braking definitely stops the member 2| (minimumspeed) and there is no friction.

In this case, the member 2| can rotate in a direction reverse to I, butthe driving torque applied on said member is small. If no antagonisticstress is opposed to this rotation, the shaft 13 remains stationary, andthe system is disengaged, that is to say the speed of the driven shaftis null. On the contrary, for a small antagonistic stress, exerted forinstance by the brake 25, the member 2| can be held completelystationary; at this moment, the driving stress, increased by the gearingdown ratio produced by the epicyclic gear is entirely applied to shaftl3, which rotates at the speed pm. For a stress comprised between 0 andthe value which stops the member 2!, the latter rotates at a greater orless speed, and,

consequently, the shaft i3 rotates at a more or less reduced speed. Thechange of speed is therefore effectedby operating the brake 25.

Thus, according to the relative value of e, on the onehand and of(R-l-T), on the other hand, the speed of the driven shaft can be causedto vary either from 0 tOpwl, or from pwl to wl. Variations of speed from0 to 601, canbe easily obtained by utilizing not a single bearing 22,but two bearings, the inner crown wheels of which have clifferent radiiR and which can be separately keyed or coupled to the driving shaft, bymeans of a suitable drive.

It is only for facilitating the explanation of the operation of theapparatus that it has been assumed that the journal 2t was rotating atthe same speed as the driven shaft is. But this condition is not in anyway necessary; it is only preferable that this journal should receive arotation in the same direction 1 as the driving shaft, for incliningaccording to vCF the reaction exerted on member 2|. In the reverse case(that is to say if the journal 20 did not rotate, for instance bydispensing with the pinions it, i 5, It or was rotating in a directionreverse'to that of the driving shaft), it would be seen that thepreceding relation (2):

R sin =Ac sin (Oi-( (2) would be replaced by the relation Rsin =Ac sin(Or- (3) which would finally give:

= (R-T) to C on the perpendicular BC to the eccentricity AB, but atanother point D as shown in Fig. 4, the direction of rotation of theaxis B about the axis A being always in the opposite direction to thearrow 1. The inner bore of member 2! then has its center at M in orderto be tangent at D to the journal 20.

In this case, which is the general case, it is obviously found that thecondition of irreversibility is fulfilled when:

AB sin =R sin +r sin (,0 (4) But: V

ABze

7r v= (+B) sin v=cos r-Hi) Therefore: 7

It will be seen that this formula gives that first found, in the case ofFigure 3, in which and in which, consequently, sin

i 'II' B *5 this being in practice equivalent to told as i is alwayssmall (Figure 5), e can assume any value different from zero since in(5) it is found that:

In this case, the system is irreversible what ever may be the value ofe.

For carrying out the arrangement shown in Figure 4, it is convenienttousethe means illustrated in Figure 6, in which the member 25 isreplaced by a double lever 3E, loosely supported by the driving shaftand receiving rollers 3i bearing at D on the eccentric journal 29. Thetheory is identically the same, of course, as in Figure 42, as will beeasily understood. e

In the example shown in Figures 1 and 2, the regulation is effected byacting on the plate of the epicyclic gear, the driven shaftbeing'driven. by a sun wheel of this epicyclic gear. The regulationmight quite as well be effected on a sun wheel, and the driving shaftmight be driven by the plate of the epicyclic gear. By way of example,Fig. 7 illustrates a form of construction of this kind, in which thedriving shaft i still actuates the sun wheel 3 which, in its turn,meshes with planet-pinions such. as 4, through the medium or not ofanother gear 25. The spindles such as 8 of the planet pinions 4 formcrank pins of eccentric cranks 2! which support a member similar to I?and. provided with the eccentric journal 2i), as in the exampleillustrated in Figs. 1 and 2. In these conditions, the journal Ziiexertson member 2i exactly the same stresses as in the preceding examples, theplate 8 actuating the driven shaft.

The connection effected between the shaft 6 and the journal 2!] is suchthat the gyration of the journal 2d (the plate 3 being assumed stoppedand the journal 29 free) obviously takes place at the same speed as therotation of shaft 5. Everything therefore occurs as if the journal asbelonged to a wheel driven through gears by shaft 6, with ratio +1 forthe first set of gears. In order that the plate 8 should be driven inthe same direction as the driving shaft, it is then necessary, as wouldeasily be seen by a simple calculation, that the ratio between 3 and 4should be negative, the magnitude of this ratio intervening only forobtaining the required gearing down ratio, or that this ratio should bepositive (use of the intermediate wheel 26), but then greater than 1. Ifit was smaller than 1, the plate would rotate in a reverse direction tothe driving shaft, and, onthe other hand, the opera tion such as it isdescribed is not possible if t ratio was equal to 1, the member italways necessarily rotating at the same: speed as shaft 2. even in thiscase, the apparatus is capable of operating, although in a mannerdifferent from those already described, provided use is made asreceiving element, no longer the plate 8, but an internally toothedcrown wheel 32 meshing with the pinions 4. Whatever may be the speed ofrotation of plate 8, the member 2| always rotates at the same speed asshaft I, and the speed of rotation of plate 8, the driven shaft beingassumed to be stopped, is determined by the number of teeth of thewheels 4 and 32. By causing the speed of rotation of plate 8 to vary,that of the receiving shaft will be caused to vary.

Now, the speed of the member 2| is due to the composition of (1) therotation of plate 8, and (2) the circular translation of the pinion 25,which corresponds to the rotation of shaft 6 in plate 8.

If the member 2| forms an irreversible connection, the circulartranslation cannot normally take place; therefore, the plate 8 rotatesat the speed of the driving shaft, the shaft 5 does not rotate, and thecrown wheel 32 is driven on direct drive. No variation of speed can beobtained by exerting a braking action on member 2|, this braking actionfurther increasing the irreversibility. On the contrary, if the member2| is reversible the circular translation can take place; normally, thesystem is therefore disengaged. The plate 8 rotates at a speed whichdepends on the ratio between 4 and 32, and the shaft 6 also rotates inthe plate 8. But, by then exerting a braking action on member 2 I, witha stress which is so much the more smaller as the system is nearer toirreversibility, this irreversibility is en sured and the circulartranslation of member 25 is thus prevented from taking place. Theconditions existing in the first case are again reached, and directdrive is attained. By variation of the braking stress on member 2|, allthe speeds are therefore passed through, from declutching to directdrive. It is true that the member 2| always rotates at the speed ofshaft i, and that during operation (except upon declutching), a brakingstress is usually exerted on said member 2|, this braking stress being amaximum for direct drive; but, even at this maximum value, the brakingstress exerted is very small, and is so much the more smaller as thesystem is nearer to the limit $1 of irreversibility and it isconsequently without practical inconvenience.

The device illustrated in Fig. 8 is a modification and a simplificationof that which has just been described. In this case, the journal 68 isdirectly secured on the driving shaft l, and the sleeve 2|], looselymounted on the same, carries a wheel 33 meshing with an internallytoothed driven crown wheel 34. It will then be understood that, on thejournal E3, the wheel 33 tends to rotate in a direction reverse to thedriving rotation assuming, of course, that the driven element 34 isstopped.

As in the case of Fig. '7, it is herein necessary that the member 2|should form a reversible connection, but as near as possible toirreversibility. If no braking stress is exerted on this member 2 thelatter rotates at the speed of shaft l, but does not prevent the looserotation of wheel 33. The system is therefore disengaged. But it will beunderstood that a small braking stress is sufficient for reachingirreversibility; at this moment, the wheel 33 cannot rotate on thejournal 28, and direct drive is obtained, the wheel 34 being driven atthe same speed as the driving shaft. By causing the braking stress tovary, all the intermediate speeds are of course passed through.

Finally, it will be noted that the devices described with reference toFigs. 3, 4 and 5 constitute new free wheels or movement selectingapparatus, which are included in the scope of the invention, as well asall their applications. Therefore, the principle of the invention wouldnot be departed from by replacing the eccentric journal and the member2| by a centered journal and wedging or propping members which could bedisengaged by an external friction.

Figs. 9 and 10 diagrammatically illustrate forms of construction inwhich (Fig. 9) the driven shaft rotates in the same direction as thedriving shaft and (Fig. 10) the driven shaft rotates in reversedirection to the driving shaft.

In the example of Fig. 9, the driven member 50 rotates about the axis 52and is driven by the driving member 5| which receives a circularmovement of translation about the axis 52. The axis 53 of member 5|moves with a gyratory movement about the axis 52. The circulartranslation of member 5| can be effected through the medium of links 54and 55 the ends 5'! and 58 of which regularly move on circular paths 56.The circular movement of translation of member 5| taking place in thedirection of the arrow 60, it causes a movement of rotation of thedriven member 50 in the direction of the arrow 5|, the arrows (i0 and 6|being in this case directed in the same direction.

In the example shown in Fig. 10, the driven member 50 is arranged withinthe driving member 5| which receives a circular movement of translationin the direction of the arrow 60. This driving member 5| is guided, asin the first case, by links 54 and 55, the free ends 51 and 58 of whichmove according to circular paths 56. The circular movement oftranslation of the member 5|, in the direction of the arrow Bil, causesa movement of rotation of the driven member 50 about the axis 52, in thedirection of the arrow 6|. In this case, the arrows 60 and 6| aredirected in reverse directions.

What I claim as my invention and desire to secure by Letters Patent is:

1. In a power-transmitting device, a driving shaft, a driven shaft, arotating member freely mounted on the driving shaft and mounted to turnabout the same axis as the driving shaft, an eccentric journal engagingwith the said rotating member mounted to turn about an axis eccentric toits center and the same as that of the driving shaft, means driven bythe driving shaft for causing said journal to move about the drivingshaft, means for kinematically connecting said journal to the drivenshaft, and means for exerting a variable braking action on the rotatingmember.

2. In a power-transmitting device, a driving shaft, a driven shaft, arotating member freely mounted on the driving shaft, a support looselymounted on the driving shaft and provided with an ecentric journalengaging with said rotating member, an intermediate shaft looselymounted in said support, means for kinematically connecting the drivingshaft and the auxiliary shaft, means for kinematically connecting theauxiliary shaft and the driven shaft, and means for braking the movementof the rotating member.

3. In a power-transmitting device, a driving shaft, a driven shaft, arotating member freely mounted on the driving shaft, a support looselymounted on the driving shaft and provided with an eccentric journal, a.sleeve freely mounted on said journal and engaging with the rotatingmember, means for causing said sleeve to rotate on said. journal, thesaid means comprising an intermediate shaft loosely mounted in thesupport, means for kinematically connecting the auxiliary shaft and thedriven shaft, and means for braking the movement of the rotating member.

4. In a power-transmitting device, a driving shaft, a driven shaft, arotating member freely mounted on the driving shaft, a support looselymounted on the driving shaft and provided with an'eccentric journal, apinion loosely mounted on said journal and provided with a hub engagingwith the rotating member, an intermediate shaft loosely mounted in thesupport, a first pinion rigidly secured on said intermediate shaft andmeshing with the pinion mounted on the journal,

a second pinion rigidly secured on the intermediate shaft, a pinionrigidly secured on the driving shaft and meshing with the second pinionrigidly secured on the intermediate shaft, a third pinion rigidlysecured on the intermediate shaft, a pinion rigidly secured on thedriven shaft and meshing with the third pinion rigidly secured on theintermediate shaft, and means for braking the movement of the rotatingmember.

5. In a power-transmitting device, a driving shaft, a driven shaft, arotating member freely mounted on the driving shaft, a support looselymounted on the driving shaft, two diametrally opposed auxiliary shaftsloosely mounted in said support, cranks rigidly secured on the saidshafts, a connecting rod connecting the said cranks and provided with acentral journal engaging with the rotating member, means forkinematically connecting the auxiliary shafts to the driving shaft,means for kinematically connecting the auxiliary shafts to the drivenshaft, and means for braking the movement of the rotating member.

CHRISTIAN DE LA BARRE DE NANTEUIL.

